Process for carrying out interactions of liquids with each other



Jan. 1, 1957 L. HABICHT 2,776,305

PROCESS FOR CARRYING OUT INTERACTIONS OF LIQUIDS WITH EACH OTHER 4Sheets-Sheet 1 Filed April 28, 1950 FIG. I. FIG.4 3| I8 32 33 H we -1 I?AIO IO 4 7 1 INVENTOR. [49 LOJO HABICHT L ax/W 4 Sheets-Sheet 2INVENTOR. LO'J 0 HABI CHT BY y 72 L. HABICHT OF LIQUIDS WITH EACH OTHERJan. 1, 1957 PROCESS FOR CARRYING OUT INTERACTIONS Filed April 28, 1950FIG.

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Jan. 1, 1957 HABICHT 2,776,305

PROCESS FOR CARRYING OUT INTERACTIONS CF LIQUIDS WITH EACH OTHER FiledApril 28, 1950 4 Sheets-Sheet 3 INVENTOR. LOJ O HABICHT United StatesPatent PROCESS FOR CARRYING OUT INTERACTIONS OF LIQUIDS WITH EACH OTHERLojo Habicbt, Hamburg, Germany Application April 28, 1950, Serial No.158,851

Claims. (Cl. 260-415) The invention relates to a process for effectingcontinuous interactions between liquids which are either immisicible orincompletely miscible. The process is applicable to the carrying out ofpurely physical procedures, e. g., solvent extractions and washing ofliquids with liquids, as well as chemical procedures such as reactionsof any sort between such liquids in which liquid reaction products ofdifferent specific weights are formed, e. g., esterification andtransesterification (alcoholysis) reactions, hydrolysis of esters, andthe like.

In carrying out known processes, pipe systems, towers or columns, andalternately arranged mixing and separating vessels are used throughwhich the two liquids are conducted countercur-rent to each other oraccording to the countercurrent principle by utilization of theirdifference in specific gravity. In order to obtain better dispersion ofthe liquids in each other, such devices as roses, nozzles, perforatedplates, packings such as R'achig rings, and stirrers have been used.These systems have failed to give satisfactory results either because oflow efliciency, due to insufficient mixing of both fluids with eachother, or because of limited capacity of throughput since the separationof the liquids depends upon gravity alone. For this reason liquids whichtend to form emulsions require apparatus of vast capacity for smallthroughput, or, where aggravated, may be impossible of treatment; alimitation which seriously restricts the field of application of thesesystems. overcome by the present invention.

An essential feature of the new process of the present best to drive theheavier liquid in a circular path through the lighter liquid bycentrifugal force.

Preferably the process is carried out by imparting rotation to bothliquids in a suitable chamber to which the heavier liquid is preferablyfed from above and the lighter liquid from below. This chamber may bestbe of cylindrical shape and where required or desired it may be ofsufficient strength to withstand high pressure and it may be providedwith means to heat or cool it externally. In carrying out the process,the major portion of the heavier liquid, which is driven by centrifugalforce into the outer zone of the chamber, is led back again into thelighter liquid in the inner zone of the chamber while the removal of theminor proportion of the heavier liquid is accomplished by paring and isregulated, in accordance with its rate of feed and any volumetric changewhich takes place in it, by the position of the interface between theliquids. The discharge of the lighter liquid takes place by overflow.

In most cases it is recommended that the process be repeated. Theforcing of the heavier through the lighter liquid will then be carriedout in a plurality of adjacent These disadvantages are 2,775,305Patented Jan. 1, 1%57 or superposed stages with application of the usualcountercurrent principle which is common in industry. In this stage-wiserepetition, the transfer of the heavier liquid from stage to stage andits final discharge is also accomplished by paring and is regulated bythe position of the interface of the liquids while the passage of thelighter liquid from stage to stage proceeds by overflow. The transferand discharge can, if desired, be regulated by utilizing the differentelectrical conductivities of the liquids across their interface.

In accordance with the invention, there is achieved a continuous,intimate intermixing and also an uninterruptedly continuing rapid andsharp separation of both liquids within a container by centrifugalforce. Preferably this is accomplished by imparting rotation to bothliquids within a cylindrical chamber by means of a rotating wingedstirring device, whereby a rapid sharp separation of the fluids iseffected. The major part of the heavy liquid driven against the outerwall of the chamber is, however, always returned from there by a conduitinto the middle of the mass of lighter liquid which fills the innersector of the chamber and then always driven through it again bycentrifugal force. The minor portion of the heavier liquid iscontinuously discharged at a rate corresponding to the rate of feed andany volumetric change. This discharge is automatically regulated by theposition of the interface, preferably by locating a paring device in theregion of the interface. The discharge of the lighter liquid takes placeat a rate corresponding to its feed and any volumetric change byoverflow.

In a plural stage process it is preferable to arrange allchambers-vertically one above the other within a closed housing throughwhich a stirring shaft runs.

The utilization of centrifugal force makes possible an uninterruptedsharp and rapid'separation and an uninterrupted intimate and rapidintermixing of both liquids whereby the volume of the heavier liquidflowing through the lighter liquid amounts to a multiple of itsthroughput volume. In this respect the present process effects asignificant acceleration over known processes with highest possibleefliciency. As a result it is possible, for example, to carry outextractions with a minimum quantity of solvent and particularly to carryequilibrium reactions to completion with a most favorable ratio ofreactants. In particular, operations involving liquids which tend toform emulsions can also readily be carried out which heretofore wereeither impossible or could be carried out only in apparatus of verylarge dimensions.

A further advantage of the invention is to be seen in the fact that,with automatic regulation of the position of the interface, an extensivecontrol of the particular interaction is made possible through widevariation in the volume and time of flow of the interacting liquidswithin the various stages of the apparatus. Furthermore the throughputratio of the interacted liquids passing from the "ap aratus isindependent of the volume ratio of interacting liquids withintheapparatus, Finally the invention oifers particularly favorableconditions for rapid heat exchange by reason of the rotation of theliquids and the passage of the heavier through the lighter from theinterior toward the exterior and back again.

The carrying out of the process is not dependent upon any particularapparatus. 'A preferred mechanism for carrying out the new processcomprises a chamber, optionally a pressure vessel, which is best ofcylindrical shape having an axially arranged stir-ring shaft providedwith stirring wings or vanes contoured to the shape of the chamber. Thechamber may be provided with heating or cooling devices. The shaft issurrounded by a perforated inlet tube for the heavier liquid. Feed linesfor the heavier and lighter liquids are arranged adjacent to the top andbottom, respectively, of the chamber. The chamber is also provided witha reflux line, a paring device and an outlet line for the heavierliquid, which latter is connected with a separating device and a returnline for the entrained lighter liquid. Finally the chamber possesses asettling space having an overflow for the lighter liquid.

Preferably a plurality of such chambers are arranged one above the otherwithin a closed cylindrical and optionally pressure resistant bodyprovided with a common central stirring shaft. In such an apparatus thewall separating adjacent chambers preferably includes one or moreintermediate feed chambers for the heavier liquid which discharge intothe perforated inlet tube of the chamber below and passages throughwhich the lighter liquid flows on its way from a lower chamber into thenext higher chamber. Optionally these passages may lead into a conicalsettling compartment extending into the chamber above to facilitateseparation of entrained heavier liquid before the lighter liquid entersthe next higher chamber.

Each reflux line for the heavier liquid discharges into a feed chamberwhich lies above the interaction chamber and which communicates with theperforated inlet tube. Each paring device is connected with a feedchamher which is arranged under the interaction chamber to serve as aseparation compartment. This feed chamber is provided with outletorifices communicating with the interaction chamber (either directly orvia a settling chamber) for passage of entrained lighter liquid.

The paring device of the lowermost reaction chamber is connected with aseparator from which the discharge of the heavier liquid preferably iscontrolled automatically according to the interface level and which isconnected to the chamber by a reflux line for the entrained lighterliquid.

Since an excellent direct heat exchange results from the rotation of theliquids on the one hand and from the circulation of the heavier throughthe lighter liquid on the other hand, an external surface heating orcooling jacket suffices for most extractions or reactions in which heatmust be added or removed during the operation. With a stronglyexothermic or endothermic processes the heavier liquid can also befurther heated or cooled in special manner during its reflux circuit.

Whether the process should be operated in one or more stages dependsupon the nature of the desired interaction. in many extractions, e. g.,those in which the material to be extracted dissolves fully in thesolvent or in washings with a cheap solvent such as water where no valueis placed upon recovery and which may therefore be used in excess, or inreactions which go to completion easily and quickly, e. g.,neutralizations, a plant having a single chamber conforming to thepresent invention suflices.

In all extraction processes, however, in which solution equilibria ofthe material to be extracted between both liquids are formed, or Wherethe solvent is to be recovered, a plant having a plurality of chambersis recommended. The number of stages is dependent upon the abovementioned equilibria. A multistage plant lends itself particularly tothe carrying out of equilibrium reactions which should be driven as faras possible to completion, such as esterifications,transesterifications, condensations, and the like. As a result of thechange in concentration of the reactants from stage to stage, whichfollows a favorable course for reactions of this type, assisted also bythe already mentioned advantage of controllability of volume andthroughout time of the liquids, which may be varied from stage to stageand during the operation, as well as the rapid heat exchange within thevarious stages, such reactions can be extensively con trolled duringtheir course and be brought to completion.

The invention may, by way of illustration but not limitation, be used inthe following instances:

Separation of sulphonic acids, sulphuric acid esters or theirneutralization products from mixtures with unreacted materials such asparaffin hydrocarbons, aromatic or alkyl aromatic hydrocarbons or theiroxidation products, fatty oils or fatty acids with solvents.

Separation of neutralization products of sulphonated, sulfo-halogenatedof sulphated organic compounds from inorganic salts such as sodiumsulphate, sodium chloride and the like with solvents.

Separation of organic acids, particularly fatty acids or theirneutralization products from mixtures with unsaponifiable constituents,e. g., oxidation products of hydrocarbons, with solvents.

Refining of fats or oils, particularly separation of free fatty acids bymeans of solvents or dilute caustic, washing of soaps from fats or oilsfollowing caustic refining by means of water or dilute salt solutions,washing and refining of crude fats or oils with acid or water.

Refining of mineral oils of natural or synthetic origin, tar oils ordistillates thereof by means of acids, liquid sulphur dioxide or organicsolvents.

Extraction of phenols from waste waters of coking operations.

Extraction of acetic anhydride from mixtures with acetic acid, as thesecome from the production of acetic anhydride, with solvents.

Extraction of phosphatides, sterols or vitamins from fatty oils by meansof solvents, fractionation of natural fats, oils or their fatty acids orof synthetic fatty acids into their individual components by selectivesolvents.

Esterification of organic acids, particularly fatty acids with alcoholsor oxyacids or transesterification of such compounds. Hydrolysis ofesters, e. g, fatty acid glycerides.

Production of fatty acid amides through the action of ammonia or amineson fatty acids or fatty acid esters.

Sulphonation or sulphation reactions, if desired those carried out withthe aid of solvents, in which either the excess sulphonating orsulphating agent, or the unsuiphonated or unsulphated organic reactantis separated continuously from the remainder of the reaction mass.

Neutralizations of sulphated or Sulphonation products in the presence ofa solvent or solvent mixture in which either the unsulphonated orunsulphated organic reactant, or the electrolyte produced in theneutralization of excess sulphonating or sulphating agent iscontinuously separated with one of the fluid phases.

Saponification of fats and oils with sodium hydroxide, to whichsufficient sodium chloride or other suitable electrolyte has been addedto produce separation of the soap formed from the glycerine-containinglye.

These examples are only 'a fraction of the numerous possibilities ofinteraction between two liquids, or materials which can be put intoliquid state, having different specific gravities Which canadvantageously be carried out by the process of the invention.

The invention will now be further disclosed and explained in conjunctionwith the drawing in which:

Fig. l is a semi-schematic vertical section of apparatus embodying theinvention taken along line Itl of Fig. 2;

Fig. 2 is a cross section through the apparatus of Fig. 1 along the line22;

Fig. 3 is a section along line 33 of the separator in Fig. 1;

Fig. 4 is a fragmentary vertical sectional view of a portion of theapparatus shown in Fig. l on a somewhat larger scale;

Fig. 5 is a fragmentary vertical section showing the operation of theparing device and the associated feed chamber;

Figs. 6 and 7 are schematic diagrams of electrical systems forregulating the position of the interface;

Fig. 8 is a semi-schematic vertical section of an appa r atiisembodyinganotlier for-m of "the iiiviitiohj Fig. 9 is a cross sectionthrough the apparatus of Fig. 8 along the line 9-9;

Fig. 10 is a semi-schematic vertical section of an apparatus embodying aform of the invention particularly adapted for making soap; and

Fig. 11 is a vertical section of the auxiliary separator used in theapparatus of Fig. 10.

Referring now to Fig. l of the drawing, the apparatus comprises a closedcylindrical, vertical vessel 1 having a bottom chamber 2, a top chamber3, and a plurality of similarly constructed intermediate chambers 4. Ashaft 5 runs axially through the chambers and is journaled in the endwalls of vessel 1 in suitable bearings 6 and 7, the former being adaptedto bear the thrust and both being so constructed as to resist leakage ofliquids under the operating pressure. Shaft 5 is 'driven by a motor 8through a speed control device 9 of any suitable type. Mounted on shaft5 for rotation therewith in each of chambers 2 and 4 are four wings orvanes 10 which are shaped to conform closely to the interior of thechamber in which they rotate with only slight clearance in order toeffect substantially nonturbulent rotation of liquids.

The lighter liquid flows through line 11 from a supply (not shown) toproportionating pump 12 which forces it through line 13 into the bottomchamber 2 adjacent to the lower end of shaft 5. Chamber 2 is providedwith a jacket 14 having an inlet 15 and an outlet 16 for heating orcooling fluid. In chamber 2 the liquid is set in rota- .6 of flow. Theminor portion of the heavier liquid, for the purpose" of furtherconduction toward'the next lower chamber 4, is taken up by one or moreparing devices 30 and run through one or more pipes 31 connectedtherewith'into one or more segmental settling chambers 29 in thepartition wall between the chambers 4, from the settling chamber 29 intothe perforated tube 17 of this chamber, and into the inner zone oflighter fluid therein.

The paring devices 30 also serve automatically to regulate the interfaceof both liquids in each chamber in that at high position of the heavierliquid more is taken out then at low position. The operation is shownbest in Fig. 5 where the interface occupies an intermediate position sothat approximately equal amounts of each liquid are taken from thechamber. Any of the lighter liquid, which is simultaneously taken up bythe paring devices 30, separates when it reaches the settling chambers29, rises to the top and returns to the chamber 4 through openings 32and settling compartment 19. In this manner the overflow of the heavierliquid takes place from chamber to chamber until it reaches chamber 2.

chambers 27 and the settling chambers 29. The only tion but due to itslesser mass it remains only in the inner A Zone of the chamber. Thelighter liquid is then traversed by streams of the heavier liquidentering'through perforations in the inlet tube 17. The heavier liquidis driven by centrifugal force to the outer zone of the chamber. As pump12 continues to operate the lighter liquid flows through a plurality oforifices 18 located in the top wall of the chamber and into a conicallyshaped settling compartment 19, as shown in Figs. 2 and 5. In thiscompartment entrained globules of heavier liquid settle out and flowback toward chamber 2. The lighter fluid then overflows the upper end ofthe conical wall of compartment 19 into a space of annular cross sectionunder a conical hood 20 which conducts it to the bottom of chamber 4. Itthen rises in the various sectors between vanes 10 which set it inrotation as described for chamber 2. In like manner it flows upwardlythrough each of the plurality of chambers 4 until it reaches the conicalsettling compartment 19 of chamber 3 which is provided with an overflowoutlet 21. The outlet 21 is connected to a discharge line 22 having afloat valve 23 to control flow of the lighter liquid from the system.

The heavier liquid flows through line 24 from a supply (not shown) toproportionating pump 25whioh irnpels it through line 26 into the upperchamber 4 by way of one or more segmental feed chambers 27 formed in thepartition wall between chamber 3 and the uppermost chamber 4. Two suchfeed chambers are shown by way of illustration in the drawing, but anydesired number may be used. Each feed chamber communicates with theperforated tube 17. Upon entering the chamber 4 through theseperforations, the heavier liquid streamlets or particles flow throughthe inner zone of lighter liquid, due to the centrifugal accelerationimparted to it, toward the outer zone of the chamber where it builds upas a somewhat hollow cylindrical mass, as shown schematically in Figs.5, 6 and 7 where the heavier liquid is shown by the heavier dashed linesand the lighter liquid by the lighter dashed lines. The major portion ofthe heavier liquid is then refluxed by the momentum imparted to itthrough one or more reflux lines 28 which communicate with chamber 4near the bottom and discharge into the segmental feed chambers 27 fromwhich the recycling heavier liquid flows again through the perforatedtube 17 into the lighter liquid and begins anew the described cycledirect connection between chambers 4 above and below the partition is byway of the passages 18 which are in the form of short tubes secured toor integral with the spaced upper and lower walls and of which six areshown in Fig. 2. To the top wall 33 is secured a short tube 35 which hasan internal diameter somewhat larger than the diameter of shaft 5. Atube 36 of the same diameter is secured to the bottom wall, spacedsomewhat from 35 to provide a discharge outlet from both chambers 27 and29, and extending some distance below the bottom wall into anenlargement 17b at the upper end of the perforated tube 17. The externaldiameter of 36 is only slightly less than the internal diameter of 17bso that practically no liquid can pass between them while stillpermitting substantially frictionless relative motion;

Extending outwardly from 35 and 36 are partition walls 37 which separatetwo oppositely located feed chambers 27 from two oppositely locatedsettling chambers 29 (Fig. 2). Within each chamber 29 is a downwardlyextending baflie 38 on the top wall and an upwardly extending baflle 39on the bottom wall located between 35 and 38. It will be seen in Fig. 5that the mixture of liquids entering settling chamber 29 separates bygravity and most of the lighter liquid rises through the two openings 32into the chamber 19. The heavier liquid passes under b'aifle 38, overbaffle 39 and out of the opening between 35' and 36 on its way to theperforated tube 17, and any lighter liquid which is entrained can flowupwardly through the opening 32 above baflle 39 into chamber 19.

The discharge of the heavier liquid from chamber 2 is effected through aparing device 40, which is advantageously located adjacent to the bottomof the chamber 2 and preferably is constructed in the shape of aperforated hollow toroid, and a discharge line 41 communicating with aseparator 42. The final discharge of the heavier liquid from the systemtakes place from the separator 42. The paring device 4% serves toregulate the interface between the two liquids in chamber 2.

The interface level in separator 42 is regulated by the solenoidoperated valve 43, which is located in heavy liquid discharge line 44.Valve 43 is operated by photocell 45 and relay 46. When the interface ofthe liquids falls to the level of photocell 45 and modifies the amountof light from the source 47 entering the cell, the relay 46 operates toclose valve 43 and stop or throttle the flow of heavy liquid from thevessel 42 until the interface rises again. The discharge line 44 extendsupwardly in the vessel 42 into the interior of a larger pipe 48,

7 which is located at one side of the vessel so as not to interfere withthe light beam and whose lower end is near the bottom of the vessel soas to provide that only heavy liquid enters through it into dischargeline 44. The lighter liquid separated from the heavier in vessel 42 isreturned by reflux line 49 to the chamber 2.

In cases where the specific gravities of liquids treated in suchapparatus are fairly constant and not too close to each other thedischarge of heavy liquid from the separator can most simply becontrolled by a floating valvethe swimming body swimming upon theinterface of both liquids. (This case is not shown in the drawing.)

In starting up the apparatus, heavier liquid is pumped through line 26into the uppermost chamber 4 while air is exhausted from the systemthrough vent valve 5%. It fills this chamber to the height of theseparating compartment 19 and then overflows into the next lower chamber4, etc., until it reaches chamber 2. As the heavier liquid rises inchamber 2 it attains a height sufficient to flow through line 41 intoseparator 42 where the level rises to the predetermined position foroperation of valve 43.

At this point the feed of heavier liquid is stopped and the valve inline 41 is closed. The motor 8 is then started to rotate shaft 5 andlighter liquid introduced as described into chamber 2 until its egressfrom overflow 21 indicates that the apparatus is full. After restartingthe feed of heavier liquid and reopening the valve in line 41, theapparatus is in continuous operation.

The dimensions of the settling compartments 19 through which the heavierliquid overflows into the next lower chamber when the vanes stand stilland the position of separator 42 are advantageously so chosen that theamount of heavier liquid initially introduced into the system in themanner described corresponds approximately with the desired operatingvolume thereof. This has the further advantage that should the rotationof shaft 5 stop for any reason during the continuous operation of theapparatus, no essential change in volume of the liquids could occur.

The regulation of the position of the interface between the two liquidsduring operation can be accomplished in ways other than the onedescribed. The discharge of heavy liquid from a chamber may, forexample, be controlled electrically by regulating the opening in valves,speed of pumps, etc., in response to the position of the interface.Illustrative types of such electrical control systems are schematicallyillustrated in Figs. 6 and 7 which are applicable where the electricalconductivities of the heavier and lighter liquids are different butfairly constant.

In Fig. 6 one interaction chamber is fragmentarily shown with theheavier liquid, represented by heavier dash lines, occupying the outerzone and the lighter liquid, represented by the lighter dash lines,occupying the inner zone. At the bottom of the chamber is an outlet line51, which may correspond either to lines 31 of chambers 4 or line 41 ofchamber 2, having a valve 52. The closure element of valve 52 isoperatively connected with a solenoid 53 in a circuit which includes asource of electric current, shown conventionally by transformer 54, andan electrically controlled switch 55. The opening and closing of switch55 is controlled by a relay 56 in a circuit which includes a source ofelectric current, shown conventionally by transformer 57, and two spacedelectrodes 58 and 59. Electrode 58 is the casing wall 1 in this case butit may be a separate electrode insulated from the casing, if desired.Electrode 59 is located somewhat inwardly of the predetermined desiredposition of the interface and it is insulated from the casing byinsulator 60. Relay 56 is so adjusted that a slight change in thestrength of the current flowing from source 57, due to deviation of theinterface from the desired position, will operate valve 52 in such a wayas to restore the interface to the desired position.

Assuming that the heavier liquid has the higher conductivity, thestrength of the current flowing from source 57 will increase as theinterface moves toward electrode 59 until it exceeds the amperagerepresenting the desired interface position whereupon relay 56 willoperate switch 55 to open valve 52 and permit heavier liquid todischarge through line 51 at a sufficient rate to restore the interfaceto the desired position. As the position of the interface moves awayfrom electrode 59, the strength of the current flowing from source 57will diminish until it falls below the amperage representing the desiredinterface position whereupon relay 56 will operate switch 55 to close orthrottle valve 52 and permit the heavier liquid to build up again in thechamber.

In case the ligher liquid has the higher conductivity, the relay 56 mustopen the valve 52 when the current from source 57 falls below theamperage representing the desired interface position, and vice versa.

Fig. 7 shows one chamber 4 fragmentarily with outlet line 51, valve 52,solenoid 53, electrodes 58 and 59 (vane 10 being notched to clear thelatter) and insulator 60 all as shown in Fig. 6, but with a differentelectrical system for controlling operation of valve 52. Referencenumeral 61 represents a source of direct current across which is avoltage divider or potentiometer 62. The electrode 58 is connected tothe negative end of potentiometer 62. The leads from the solenoid 53 areconnected, respectively, to the positive end of potentiometer 62 and tothe plate 63 of a triode 64. Electrode 59 is connected to the grid 65 oftriode 64 while the heated filament 66 thereof is connected to thevariable potentiometer lead 67. The magnetic force of solenoid 53tending to move the closure element of valve 52 is counterbalanced by amechanical force, e. g., a spring 68, which forces are always inequilibrium.

Assuming the heavier liquid to have higher conductivity than the lighterliquid, the magnetic force of solenoid 53 is arranged to open valve 52so that as the interface moves toward electrode 59 and more currentflows in the electrode circuit, there is a corresponding increasedcurrent flow in the solenoid circuit which opens valve 52 and permitsthe heavier liquid to discharge through line 51 at a greater rate. Asthe interface recedes from electrode 59 less current flows in theelectrode circuit and in the solenoid circuit, thus permitting thespring 68 to close valve 52 and diminish the rate of discharge of theheavier liquid. The predetermined position of the interface can beregulated by moving the lead 67 along the potentiometer.

If the lighter liquid has higher conductivity than the heavier liquid,the system is simply altered so that the mechanical force tends to openand the magnetic force tends to close the valve 52.

In the control systems of Figs. 6 and 7 there is practically no lighterliquid withdrawn through line 51, thus differing in this respect fromwithdrawal of liquids by a paring device 30 into line 31, as shown inFig. 5. For this reason the openings 32 and baffles 38 and 39 can bedispensed with and it is not necessary to use the partitions 37 toseparate the feed and settling chambers 27 and 29 where a control systemis employed which operates in the manner of Figs. 6 and 7.

The apparatus illustrated in Figs. 8 and 9 is somewhat simpler inconstruction than that of Figs. 1 and 2 and can be used with advantagewhere the reflux lines do not need to be used for heat exchange and/orregulation at intermediate stages. It comprises a closed cylindricalvertical vessel 1a having a bottom chamber 2a, a top chamber 3a and aplurality of similarly constructed intermediate chambers 4a. A shaft 5aruns axially through the chambers and is journaled in the end Walls ofvessel 3 in suitable bearings 6a and 70, as already described for thecorresponding parts of the apparatus of 9 Fig. 1. Other partswhichcorresp'ond with those of Fig. I bear the same reference numbersplusthe letter a and need not be further described.

The partition between adjacent chambers in the apparatus of Fig. 8 has adifferent construction from that between the chambers of the apparatusof Fig. 1 and it serves to recycle heavier liquid within a chamber, as aparing device for controlling the interface, and to pass heavier liquiddownwardly and lighter liquid upwardly from chamber to chamber.Structurally it comprises a top plate 70 extending from the casing in tothe shaft a which rotates in it with a minimum of clearance necessaryfor frictionless rotation, a bottom plate 71 Which is spaced from boththe casing in and the shaft 5a, and a plurality of curved vertical wallsconnecting the top and bottom plates. Certain of these designated 72form recycle or reflux channels 73 (Fig. 9) which are adapted to pick upheavier liquid at the periphery of a chamber due to its rotary motion(clockwise in Fig. 9) and conduct it into a tube 74 which communicateswith perforated tube 17a in the same manner that 36 communicates with17. Other vertical walls designated 75 of arcuate shape connect'theperiphery of bottom plate 71 between channels 73 with the top plate 70,forming open bottom feed conduits 76 which empty into channels 73 on theoutside thereof and settling chambers 77 on the inside thereof.

An arcuate paring slot78 is provided in the top plate for each settlingchamber 77 at the desired position of the interface. A mixture of thelighter and heavier liquids passes from the chamber above through paringslots 78 into the settling chamber 77 in the same way already describedfor paring device 30. Here it passes under a bafile 79 along the edge ofslot 78, under a baffle 80 along the edge of a second arcuate slot 81and over a baflle 82 on the bottom plate 71. A third arcuate slot 83 isformed in the top plate above the settling chambers near a conicalarcuate wall 84 and a similar slot 85 is formed in the bottom plate 71.The baffle 79 largely prevents lighter fluid which separates in chamber77 from flowing back into chamber 4a through paring slot 78 and thusdirects most of it, with the aid of baflle 80, through slot 81.Additional lighter liquid which separates returns through slot83. Theheavier liquid is held back to some extent by baffle 82 to assure asettling time, that which flows over it passing downwardly through slot85 into the chamber below where centrifugal force throws it outwardly.The lighter liquid flows from a lower chamber into a higher chamberthrough the passages between tube 74 and conical walls 84. It will benoted that the perforations in tube 17a terminate some distance belowplate 71 which practically assures removal of heavier liquid enteringthrough the perforations before the lighter liquid enters thesepassages.

Chamber 3a also is provided with vanes a to assure separation of anyentrained heavier liquid before the lighter liquid overflows into outlet21a. By reasons of the sloping top wall of casing 1a, all segregatedheavier liquid leaves chamber 3a through slots 78 without building up arotating mass.

In starting up the operation in the apparatus of Figs. 8 and 9 the valvein line 41a is closed and lighter liquid is fed in until the lower part,e. g., the lowermost chamber, is filled. Heavier liquid is then pumpedin through line 26a, preferably at a higher rate than desired for finalcontinuous operation while lighter liquid continues to be fed throughline 13a and motor 8a is started. As soon as heavier liquid reaches thelowermost chamber, the valve in line 41a is opened. When the lighterliquid begins to discharge through line 21a the rates of feed of lighterand heavier liquids are adjusted to the desired ratio. The finalregulation of the interface position in the various chambers takes placeautomatically.

The following working examples are given for the purpose of illustratingbut not limiting the invention:

Example I Using the apparatus of Fig. l in the manner previous-- lydescribed, an overhead vacuum-distilled lubricant stock at a temperaturewithin the range of about 100 to 250 F is pumped through line 13 intothe bottom of the vessel 1 and furfu-ral at about the same temperatureis pumped through line 26 into the uppermost chamber 4. Theproportionating pumps 12 and 25 are set to deliver about twice as muchby weight of furfural per unit time as hydrocarbon (solvent ratio about2:1). The light raffinate is removed from the top via line 22 to araflinate stripper and the heavier extract phase, after separation fromentrained lighter liquid in separator 42 is removed by way of line 44 toan extract stripper. The solvent recovered from both strippers isreturned to a storage vessel connected with line 24. The refined oilfrom the raffinate stripper is of excellent quality indicating verythorough separation.

Example 11 Using the apparatus of Fig. 8 in the manner previous- 'lydescribed, except that pressure release valves are provided in lines 22aand 44a, liquid propane is pumped into vessel 1a through line 13a whilea heavy asphaltic crude residuum is pumped into the uppermost chamber 4athrough line 26a. The proportionating pumps 12a and 25a are set todeliver about five times as much by weight of liquid propane per unittime as hydrocarbon (solvent ratio 5:1). The temperature of the liquidsis within the range of about to F. The lighter extract phase is removedfrom the top of the tower and run to propane evaporators and a stripperof conventional types, the recovered propane being returned to a storagevessel connected with line 11a. The heavier rafiinate phase removedthrough line 44a passes to a furnace, to a flash drum and finally to astripper all of conventional type, the recovered propane being returnedto said storage vessel. The oil recovered from the extract phase issatisfactorily de-asphalted.

Example 111 Using the apparatus of Fig. 1 in the manner alreadydescribed except that air or inert gas under suitable pressure issupplied through valve 50 and pressure release valves are used in lines22 and 44, liquid fat is pumped into chamber 2 at a tempature of about40 to 100 C. while unheated water is pumped into the uppermost chamber4. The proportionating pumps 12 and 25 are set to deliver about half asmuch water by weight per unit time as fat (solvent ratio about 1:2). Thereflux lines 28 for the bottom chamber 4 and the next to the top chamber4 pass through Dowtherrn heat exchangers which raise the temperature ofthe liquids in these intermediate reaction chambers within the range of200 to 270 C. The rates of flow are controlled so that the fat to behydrolyzed is at the hydrolyzing temperature for about 30 to minutes.The end chambers serve as direct heat exchangers for cooling theoutgoing sweet water and fatty acids and preheating the incoming fat andwater, thus making the heat efficiency of the system very high. Freefatty acids are removed through line 22 with a low dissolved watercontent because of the effective heat exchange with the incoming waterand the efiiciency of separation of heavier from lighter liquid. Sweetwater of relatively high glycerine content is removed through line 44.The pressure of the air or inert gas supplied through valve 50 is atleast equal to and preferably somewhat higher than the pressure ofsaturated steam at the highest temperature in the system so as toprovide smooth operation and to assure retention of water in liquidphase.

In carrying out the hydrolysis of fat in the manner described, it isadvantageous to provide about three times more volume in the lowermostreaction chamber, i. e.,

the lowest chamber 4, than in succeeding reaction chambers. In this waythe hydrolysis reaction can be carried to about 60% to 75% of completionin the first reaction chamber 4 which has a number of advantages. One isthat up to this degree of hydrolysis the rate of reaction issubstantially independent of the concentration of glycerol in theaqueous phase. This makes it possible to operate the system to yield afairly concentrated sweet water without adversely affecting thethroughput rate or the final degree of hydrolysis. the fact that at thisdegree of hydrolysis the solubility of water in the fatty phase hassubstantially reached its maximum. The fresh oil entering this chamberis therefore dissolved in a fatty phase of high water content underoptimum conditions for very rapid reaction. The slow starting rate ofhydrolysis due to low solubility of water in the fresh oil is therebyavoided.

Example IV Using the apparatus of Fig. 8, except that it is completelyjacketed to provide uniform temperature throughout, liquid fat, e. g, atallow-coconut oil blend, is pumped into chamber 2a while an aqueousbrine and caustic soda solution, or a separate solution of each, ispumped into the uppermost chamber 4a at a rate so proportioned withrespect to the fat feed rate as to provide two liquid phases and aslight stoichiomctric excess of caustic. While the concentration ofcaustic and brine may vary over a wide range, a solution containing 5%to caustic as Nest) and S to 12% NaCl is satisfactory. The temperatureof the reacting liquids is maintained at about 100 C. Liquid neat soapis removed through line 22a and the spent lye containing liberatedglycerine is removed through line 44a.

It is advantageous to be able to carry out the necessary washing,fitting and settling operations within the same piece of apparatus andthis can be accomplished by providing additional stages as disclosed inFig. 10. The apparatus of Fig. 10 being generally the same as that ofFig. 8, all parts which are the same in both embodiments have been giventhe same reference numerals in Fig. 10 as in Fig. 8 except that theybear postscript I) and no further description of the structure of theseparts need be given. It will he observed that the entire vessel 1b isjacketed at 14b to provide temperature control. Nine interactionchambers designated I to I X, going upwardly, are provided for carryingout the following operations:

Chamber or Stage Operations A second advantage depends upon I Chambers Ithrough VI have the same construction as chambers 2a and 4a of Fig. 8.Chamber VII is the same except that the partition between it and chamberVIII has only reflux lines and passages near the shaft for flow oflighter liquid from VII into VIII similar to the passages between '74and 84 in the other partitions. Chamber VIII, instead of having vanesNib secured to a perforated tube 17 as in chambers I to VII, is providedwith an efficient mixing device 86, e. g., a turbo-mixer. A simpiepartition 8''! provided with a plurality of orifices separates chambersVIII and IX.

Chamber IX is provided with vanes 19b for rotating the liquids thereinso as to effect centnifugal separation of the liquid neat soap from theliquid nigre. The chamber wall preferably diverges from both ends toassure a layer of nigre of considerable thickness despite the relativelysmaller volume thereof compared to the neat soap and to provide forremoval of neat soap through outlet 21b and nigre through outlet 89which communicate with chamber IX on opposite sides of the interfacebetween these phases. The orifices 88 preferably are located near theinterface. A proportioning pump 90 in nigre outlet line 89 returns thenigre to the bottom of chamber VII at a controlled rate. If desired, thenigre can be drawn off for treatment or use outside the tower.

A caustic tank 91 has a feed line 92 communicating with reflux conduit76b of the partition above chamber II. Flow of caustic solution throughline 92 is regulated by a feed regulator 93 under the control of anautomatic device 94 which preferably continuously samples the aqueousphase in the outer layer of chamber II. A second caustic feed line 95provided with a proportionating pump 96 supplies caustic to the refluxconduit 76b of the partition above chamber VI. A third caustic feed line97 provided with a feed regulator 98 supplies caustic to the refluxconduit 76b in the partition above chamber VII, this How beingcontrolled by an automatic device 99 which preferably continuouslysamples the aqueous phase in chamber VII.

A brine tank 100 has a feed line 191 communicating with the refluxconduit 76b in the partition above chamber VII, the how of brine beingcontrolled by a feed regulator 192 under control of an automatic deviceH33 in the same sampling line as control 99. A second brine feed line104 supplies brine to chamber VIII by means of a proportionating pump105.

The fatty material to be saponified is brought through supply line 11band fed into chamber I through line 1312 by pump 12b. Water isintroduced into chamber VIII through line 26b by pump 25b. Spent lyeleaves chamher I through paring device 40b and discharge line 4211 Whereit is discharged into separator 4212. As seen in Fig. 11, the outletline 44b is provided at the upper end with a valve 106 which isconnected by stem 107 with the cross bar 108 of an annular float 109which is adapted to float at the interface between a fatty phase and anaque ous phase which separate by gravity in separator 42b. It will beapparent that if the level of the lower spent lye phase rises, thefloats will open the valve to permit the spent lye to flow out throughline 44b but that the flow will cease when the level falls near theupper end thereof. Fatty material is returned through line 49b tochamber I.

The lowermost chamber I in which the fatty material is introduced at anysuitable temperature above the melting point serves for neutralizing thelye coming from the chambers above. During this process any free fattyacids of the fat composition introduced through line 131) are used upand a partial saponification of neutral fat takes place. The degree ofsaponification obtained in this chamber may range between 10 to 20%. Inchamber II the main part of the saponification takes place byinteracting the fatty phase with a lye of not too high a proportion ofNazO, e. g., about 2% to 4%, which can be neutralized within the firststage. The proper concentration of NazO within the aqueous phase is keptconstant by regulated feed of the small additional amount of causticnecessary for saponification in this stage through line 92. The mainamount of alkali comes from the stages above. This chamber, in which adegree of saponification between 75 and 90% may he obtained, istherefore preferably of larger size than the other chambers. Controldevice 94 may be a pH meter for making continuous determination of thealkali by pH measurement of a mixture of a continuously withdrawn samplewith a suitable buffer solution. The electromotive force generated inthe electrodes of the meter can then be utilized to control the feedregulator 94 which may be of any suitable design, such as a variablespeed feed pump, diaphragm valve, etc.

Saponification will go practically to completion in the next higherchamber III where the fatty material contacts an aqueous phase which maycontain about 6% to 9% NazO. The degree of completion of thesaponification can t in be checked, e. g., by withdrawing a sample ofsoap either continuously or intermittently through line 1% and mixing itwith distilled water to form a solution which can be tested forturbidity by mere observation or by means of a photo-electric cell. Sucha measuring instrument is indicated at 107, with the testing solutionbeing returned to the system through line 108. By proper calibration ofthe instrument or by comparison of the test solution with standardizedsolutions the operator can ascertain whether the reaction has proceededto a satisfactory degree of completion. If it has gone further thanrequired, the rate of feed of the reactants may be increased, ifdesired, whereas if it has not gone far enough the rate of feed of thereactants should be diminished.

Any slight residue of unsaponified material in the liquid which flowsfrom chamber III into IV is saponified in the next washing stages inchamber IV to VI where contents of NazlO rise to about 8 to 10% due tothe fact that practically no consumption of NazO takes place in thesestages. The main quantity of caustic is introduced into chamber VIthrough line 95 in a continuous constant proportion by theproportionating pump 96.

In the uppermost washing stage in chamber VII the amount of brinenecessary for separating soap from spent lye in the earlier orsaponilfication stages is brought into the system. If this is the laststage carried out in the apparatus, e. g., if the soap which is now in acondition to be fitted is removed from the apparatus and treated in akettle in the usual Way for fitting and settling, the brine isintroduced by a proportionating pump. On the other hand if the fittingand separating stages are carried out in succeeding stages in acontinuous manner within the same closed vessel, as is preferred, aregulation of the concentration of NazO and NaCl within the aqueoussolution of the uppermost washing stage is necessary in order to impartto the soap which enters the fitting chamber VIII such amounts of bothelectrolytes that after mixing with constant amounts of Water and/oradditional brine, conditions will be obtained providing the desiredratio of appropriate neat soap and nigre in the final separating stagein chamber IX.

Regulation of concentration of NazO within the uppermost washing stagein chamber VII can be accomplished in a similar way as it is done in thesecond saponifying stage in chamber II by controlled feed of slightadditional amount of caustic through line 97 and feed regulator 98 undercontrol of a pH meter W. Regulation of the concentration of sodiumchloride may be accomplished by control 163 either by checkingelectrical conductivity or the chlorine potential of the aqueous phaseand governing hereby feed of brine through line 101 by feed regulator102.

The soap thus being adjusted in an indirect manner enters the fittingchamber VIII where it is mixed continuously with constant amounts ofwater introduced through line 26b by pump 25b and additional brineintroduced through line 104 by pump 105.

From this fitting stage the soap passes continuously to the separatingchamber IX where the soap is subjected to centrifugal force asdescribed, and separated thereby into neat soap and nigre. In order tofacilitate separation, the finished soap preferably enters theseparating chamber through orifice 88 at a distance from the shaft nearthe interface between neat soap and nigre. The nigre which is drawn offcontinuously from the outside of the chamber through line 89 is fed backinto a washing stage. The nigre may be introduced into chamber Vi if itcontains a relatively large amount of impurities, but in general it ispreferably introduced into chamber VII as shown in Fig. 10 for betterutilization of the countercurrent principle.

It will be understood that all of the proportionating pumps used in thissystem, i. e., pumps 12b, 25b, 90, 96 and 105, will be interconnected sothat the flow rate of the incoming fat can be increased or decreasedwithout '14 disturbing the proportional rates of flow of the othermaterials. Each pump will also be separately adjustable so as to enableproper setting of its rate of feed or flow independently of a change inthe rate of the other pumps.

The described process of executing the saponifying, purifying, fittingand separating operations within one apparatus has not only theadvantage of technical simplicity and economy but also the advantagethat the caustic solution necessary for saponifying the fat can be usedfor the washing operations as Well, thus providing a minimum bulk of lye(i. e., a low ratio of spent lye to fat), highest recovery of theglycerin and highest glycerin concentration of the spent lye.

The apparatus described and illustrated in the present patent forms thesubject matter of my co-pending application S. N. 324,579 filed December6, 1952.

Although the invention has been described and illustrated in conjunctionwith certain specific embodiments, it will be understood that it iscapable of broad application and that variations and modifications ofstructure and operating procedures may be made without departing fro-mthe spirit and scope of the invention as set forth in the appendedclaims.

What is claimed is:

l. The process of interacting two liquids of different specificgravities which at most are only partially miscible which comprisesrapidly rotating a mass containing both liquids around a vertical axisin an annular chamber filled therewith whereby the mass is in the formof a somewhat cylindrical body with the heavier liquid filling an outerzone and the lighter liquid filling an inner zone thereof, there being asomewhat cylindrical interface between said heavier and lighter liquids,introducing heavier liquid into the inner cylindrical surface of saidliquid body at a plurality of locations so that it passes in dispersedform through the body of lighter liquid into the body of heavier liquidby centrifugal force, withdrawing a mixture of heavier and lighterliquid from the body across said interface, the rate of withdrawal ofthe heavier liquid in said mixture corresponding to said rate ofintroduction of heavier liquid, separating said mixture into heavier andlighter liquds, returnng said separated lighter liquid to said rotatingmass, introducing lighter liquid into said liquid body adjacent to thebottom thereof, withdrawing lighter liquid from the top of the bodythereof in said inner zone, withdrawing a stream of heavier liquid fromthe outer zone and reintroducing it into said mass at a plurality oflocations on the inner cylindrical surface of the lighter liquid so thatit passes in dispersed form through the lighter liquid in the inner zoneinto the heavier liquid in the outer zone by centrifugal force.

2. The process of interacting two liquids of different specificgravities which at most are only partially miscible which comprisesrapidly rotating a mass containing both liquids around a vertical axisin an annular chamber filled therewith whereby the mass is in the formof a somewhat cylindrical body with the heavier liquid filling an outerzone and the lighter liquid filling an inner zone thereof with asomewhat cylindrical interface between the two liquids in said body,introducing lighter liquid into said liquid body adjacent to the bottomthereof, withdrawing lighter liquid from the top thereof inside saidinterface, introducing heavier liquid into said liquid body, withdrawinga mixture of heavier and lighter liquid from the body across theinterface, separating said mixture, returning the separated lighterliquid to said body, Withdrawing heavier liquid from the body outsidesaid interface for recycling and reintroducing it into said mass at aplurality of locations on the inner cylindrical surface of the lighterliquid so that it passes in dispersed form through the lighter liquid inthe inner zone into the heavier liquid in the outer zone by centrifugalforce.

3. The process as set forth in claim 2 in which the 15 position of theinterface between the two liquids in the rotating mass is controlled bythe ratio of heavier and lighter liquids in the mixture withdrawn fromsaid body across the interface.

4. The process for interacting two liquids of different specificgravities which at most are only partially miscible which comprisesrotating a plurality of masses containing both liquids around a singlevertical axis in a plurality of vertically related annular chambersfilled therewith whereby each mass is in the form of a somewhatcylindrical body with the heavier liquid filling an outer zone and thelighter liquid filling an inner zone thereof with a somewhat cylindricalinterface between the two liquids in said body, introducing lighterliquid into the lowermost body, withdrawing lighter liquid from eachbody inside said interface and passing the withdrawn lighter liquid fromeach body except the uppermost into the next higher body, introducingheavier liquid into the uppermost body, withdrawing a mixture of heavierand lighter liquids from each of said bodies across said interface,separating each mixture, reintroducing the separated lighter liquid intothe same body from which it was withdrawn, passing the separated heavierliquid from each body except the lowermost to the next lower body,withdrawing heavier liquid from each body outside the interface andrecycling it to the inner cylindrical surface of the same body through aplurality of locations so that heavier liquid recycles repeatedly indispersed form through each body of lighter liquid into each body ofheavier liquid by centrifugal force.

5. The process of refining a petroleum fraction such as lubricating oilfraction which comprises rapidly rotating a mass comprising suchfraction and a suitable solvent being heavier than this fraction at asuitable temperature around a vertical axis in an annular chamber,whereby the mass is in the form of a somewhat cylindrical body with thesolvent filling an outer zone and the petroleum fraction an inner zonetherein with a somewhat cylindrical interface between them, introducingthe petroleum fraction to be extracted into said mass adjacent to thebottom thereof, withdrawing extracted petroleum fraction inside saidinterface at the top thereof, withdrawing for recycling a stream ofsolvent outside said interface and reintroducing it at a plurality oflocations into the inner cylindrical surface of the petroleum fractionin the inner zone, introducing fresh solvent into the system, withdrawing a mixture of solvent and petroleum fraction across theinterface, separating the mixture and returning the separated petroleumfraction to the rotating mass.

6. The process as set forth in claim in which the process is carried outin a plurality of like stages in accordance with continuous countercurrent principles with the petroleum fraction entering the lowermoststage and the solvent the uppermost stage.

7. The process of refining a petroleum fraction which comprises rotatinga mass comprising such fraction and a suitable solvent lighter than thisfraction at a suitable temperature around a vertical axis in an annularchamber, whereby the mass is in the form of a somewhat cylindrical bodywith the fraction filling an outer zone and the solvent an inner zonetherein with a somewhat cylindrical interface between them, introducingthe solvent into that mass adjacent to the bottom thereof, withdrawingsolvent containing extracted material inside the interface at the topthereof, withdrawing for recycling a stream of the fraction outside theinterface and reintroducing it at a plurality of locations into theinner cylindrical surface of the solvent in said inner zone, introducingfresh petroleum fraction into the system, withdrawing a mixture ofsolvent and extracted fraction across the interface, separating saidmixture, and returning the separated solvent to said rotating mass.

8. The process as set forth in claim 7 in which the process is carriedout in plurality of like stages in accordance with continuouscountercurrent principles with 16 the solvent entering the lowermoststage and the petroleum fraction the uppermost stage.

9. The process of hydrolyzing fatty esters which comprises rapidlyrotating a mass comprising fatty esters and water at hydrolyzingtemperature around a vertical axis in an annular chamber, whereby anaqueous liquid fills an outer zone and a fatty phase in inner zonetherein with a somewhat cylindrical interface between them, introducingfatty esters to be hydrolyzed into said mass adjacent to the bottomthereof, withdrawing fatty material from said inner zone inside saidinterface at the top thereof, recycling aqueous liquid from the outerzone outside said interface through the fatty phase in the inner zonewithdrawing a mixture of fatty material and aqueous liquid across theinterface, separating the mixture, returning the separated fattymaterial to the rotating mass and introducing fresh water into thesystem.

it), The process as set forth in claim 5 in which the process is carriedout in a plurality of like stages in accordance with continuouscountercurrent principles with the fatty esters entering the lowermoststage and the water the uppermost stage.

11. The process for saponifying fatty material which comprises rapidlyrotating a two-phase mass comprising fatty material and an aqueoussolution of electrolyte and saponifying agent at a suitable temperaturearound a vertical axis in an annular chamber, whereby the mass is in theform of a somewhat cylindrical body with the aqueous solution filling anouter zone and the fatty material an inner zone therein with a somewhatcylindrical interface between them, introducing fatty material to besaponified into said mass adjacent to the bottom thereof, withdrawingsaponified fatty material from the inner zone inside said interface atthe top thereof, withdrawing a stream of the aqueous solution outsidesaid interface and reintroducing it at a plurality of locations into theinner cylindrical surface of the fatty material in the inner zone,withdrawing a mixture of aqueous solution and fatty material across saidinterface, separating said mixture into aqueous solution and fattymaterial, returning the separated fatty material to the rotating massand introducing fresh aqueous solution of electrolyte and saponifyingagent into the system.

12. The process as set forth in claim 11 in which the saponification iscarried out in a plurality of stages in accordance with continuouscountercurrent principles with the fatty material entering the lowermoststage and the fresh aqueous solution the uppermost stage.

13. The process as set forth in claim 12 in which fresh aqueous solutionof saponifying agent is also introduced at an intermediate stage.

14. The process of purifying saponification products of fatty glycerideswhich comprises rapidly rotating a mass comprising such saponificationproducts and an aqueous solution of an electrolyte at a suitabletemperature around a vertical axis in an annular chamber, whereby themass in in the form of a somewhat cylindrical body with the aqueoussolution filling an outer zone and the saponification products an innerzone therein with a somewhat cylindrical interface between them,introducing saponification products to be purified into said massadjacent to the bottom thereof, withdrawing purified saponificationproducts from the inner zone inside said interface at the top thereof,withdrawing a stream of the aqueous solution outside said interface andreintroducing it at a plurality of locations into the inner cylindricalsurface of the saponification products in said inner zone so that itpasses in dispersed form through the saponified products in the innerzone, withdrawing a mixture of said aqueous solution and saponificationproducts across said interface, separating said mixture into the aqueoussolution and saponification products, returning the separatedsaponification products to the rotating mass and introducing additionalaqueous solution of electrolyte into the system.

15. The process as set forth in claim 14 in which the process is carriedout in a plurality of similar stages in accordance with continuouscountercurrent principles.

References Cited in the file of this patent UNITED STATES PATENTSSharples July 3, 1917 Wait Apr. 29, 1924 Podbielniak July 30, 1940Podbielniak June 9, 1942 m Tomlinson Aug. 4, 1942

1. THE PROCESS OF INTERACTING TWO LIQUIDS OF DIFFERENT SPECIFICGRAVITIES WHICH AT MOST ARE ONLY PARTIALLY MISCIBLE WHICH COMPRISESRAPIDLY ROTATING A MASS CONTAINING BOTH LIQUIDS AROUND A VERTICAL AXISIN AN ANNULAR CHAMBER FILLED THEREWITH WHEREBY THE MASS IS IN THE FORMOF A SOMEWHAT CYLINDRICAL BODY WITH THE HEAVIER LIQUID FILLING AN OUTERZONE AND THE LIGHTER LIQUID FILLING AN INNER ZONE THEREOF, THERE BEING ASOMEWHAT CYLINDRICAL INTERFACE BETWEEB SAID HEAVIER AND LIGHTER LIQUIDS,INTRODUCING HEAFIER LIQUID INTO THE INNER CYLINDRICAL SURFACE OF SAIDLIQUID BODY AT A PLURALITY OF LOCATIONS SO THAT IT PASSES IN DISPERSEDFORM THROUGH THE BODY OF LIGHTER LIQUID INTO THE BODY OF HEAVIER LIQUIDBY CENTRIFUGAL FORCE, WITH DRAWING A MIXTURE OF HEAVIER AND LIGHTERLIQUID FROM THE BODY ACROSS SAID INTERFACE, THE RATE OF WITHDRAWAL OFTHE HEAVIER LIQUID IN SAID MIXTURE CORRESPONDING TO SAID RATE OFINTRODUCTION OF HEAVIER LIQUID, SEPARATING SAID MIXTURE INTO HEAVIER ANDLIGHTER LIQUIDS, RETURNNG SAID SEPARATED LIGHTER LIQUID TO SAID ROTATINGMASS, INTRODUCING LIGHTER LIQUID INTO SAID LIQUID BODY ADJACENT TO THEBOTTOM THEREOF, WITHDRAWING LIGHTER LIQUID FROM THE TOP OF THE BODYTHEREOF IN SAID INNER ZONE, WITHDRAWING A STREAM OF HEAVIER LIQUID FROMTHE OUTER ZONE AND REINTRODUCING IT INTO SAID MASS AT A PLURALITY OFLOCATIONS ON THE INNER CYLINDRICAL SURFACE OF THE LIGHTER LIQUID SO THATIT PASSES IN DISPERSED FORM THROUGH THE LIGHTER LIQUID IN THE INNER ZONEINTO THE HEAVIER LIQUID IN THE OUTER ZONE BY CENTRIFUGAL FORCE.